Hi Sarah,
I spent a week in Cape Town and I will try to help you a little. Cape Town is a fantastic city, it's not that big but there's plenty to see and do. Everything is close, as in no more than a 30 mins away. You do not need a car if you want to spend all your time right in Cape Town. They have cabs and the buses are dirt cheap, pay one small price and ride all day.
Here are some things to do right in Cape Town. Go on a bus tour through the city, it's on a Double Decker bus. Go to the top of Table Top mtn, this will take a half of day. Go to Robyn Island, again about half a day spent. A must is the Victoria Water Front. You can spend a lot of time there. There are shops, restaurants, boat rides, etc. You can take a boat ride out to see the whales. Go Great White shark diving (in a cage), plus much more.

If you have a car take a drive down the coast. Great beaches. Go to Simons Town and see the penguins. Go to the Cape of Good Hope. Drive about another hour and go to Cape Agulhas, that's where the two Oceans meet. If you do this drive leave early in the morning as this will take all day. You will walk a lot at the Cape of Good Hope. There are steps and trails to the top. It will be a lifetime thing to do, A MUST! Also walk down the steps to the beach. All I need to say is have a camera.

Wine country is about an hour and more north of Cape Town. Nice hills and country side. You can go on wine tours out of Cape Town. Also take a Safari tour out of cape Town. There are many different types of tours you can take. Most tours will pick you up at your hotel and include lunch.

Money, US dollars are ok, most will take them. You can go to a ATM and put in your card and get Rand Dollars out. The exchange rate will be good. The only person or business that didn't take US dollars was a cab driver. I thought this was neat. At a resterant the bill came in 4 different curancy, Rand, US dollars, Euros, and English Puonds.

If you have any questions you may PM me. This is a good start for you. Enjoy!
www.sailhoneycat.com
Greg